Workers clean the glass roof of the “New Century Global Centre“ building, which opened to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

A water park is seen in the “New Century Global Centre“ building which opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building (top) is seen standing among several buildings in Chengdu, in southwest China’s Sichuan province on June 6, 2013. The center, claimed by Chinese officials as “the world’s largest standalone structure“, is going to be opened to the public on June 28. The 100m high “New Century Global Centre“ is a symbol of the spread of China’s boom: 500m long and 400m wide, with 1.7 million square metres of floor space - big enough to hold 20 Sydney Opera Houses, according to local authorities. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

Workers make last minute preparations at a water park in the “New Century Global Centre“ building, which opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building opens to the public in Chengdu, southwest China’s Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be “the world’s largest standalone structure“, measuring 500 metres in length and 400 metres in width, with 1.7 million square metres of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China’s economic boom. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

This picture taken on May 26, 2013 shows the “New Century Global Centre“ building behind an artificial lake in Chengdu, in southwest China’s Sichuan province. The center, claimed by Chinese officials as “the world’s largest standalone structure“, is going to be opened to the public on June 28. The 100m high “New Century Global Centre“ is a symbol of the spread of China’s boom: 500m long and 400m wide, with 1.7 million square metres of floor space - big enough to hold 20 Sydney Opera Houses, according to local authorities. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)

The “New Century Global Centre“ building is seen behind an artificial lake in Chengdu, in southwest China’s Sichuan province on June 6, 2013. The center, claimed by Chinese officials as “the world’s largest standalone structure“, is going to be opened to the public on June 28. The 100m high “New Century Global Centre“ is a symbol of the spread of China’s boom: 500m long and 400m wide, with 1.7 million square metres of floor space - big enough to hold 20 Sydney Opera Houses, according to local authorities. CHINA OUT AFP PHOTO (Photo credit should read STR/AFP/Getty Images)